The invention relates to a method of connecting a rotationally symmetrical part to a hub part by welding, the contact surfaces to be connected to one another being essentially cylindrical and the rotationally symmetrical part having functional surfaces, the accurate position and/or angle of which is essential to the function. The expression “functional surfaces” refers, for example, to the rolling surfaces of a gear or to the sealing surfaces of a pump rotor. The expression “essentially cylindrical” means that the contact surfaces are not surfaces normal to the axis but exert a certain centering effect. The hub part may also be part of the shaft carrying the rotationally symmetrical part or may be this shaft itself. In the case of gears, consideration is given in particular to the crown wheel of an axle drive for motor vehicles, the shape and position of the functional surfaces of said crown wheel resulting in high susceptibility to angular distortions due to welding stresses, but especially high demands are imposed on the accuracy of the engagement with said crown wheel.
Such rotationally fixed connections between shaft and hub or between a hub and a rotationally symmetrical part are normally produced merely by pressing on or by shrinking on, with especially high and fluctuating forces, as occur inter alia, for instance, at the crown wheel in the axle drive of a motor vehicle, by high-strength body-fit bolts. However, the connection by means of body-fit bolts is costly and requires considerable construction space. Welded connections are also conceivable, but are not advisable where there are functional surfaces of high accuracy on account of the welding distortion.